This invention relates to a device and method for measuring mass flow.
To compute mass flow both the flow velocity and fluid density must be known. It is known how to use a vortex flowmeter to measure a shedding frequency proportional to the flow velocity (f.sub.1 =k.sub.1 V), and to measure the average drag force (A.sub.1) on an object in a flowstream which is proportional to the fluid density (.rho.) and the flow velocity squared (A.sub.1 =c.sub.1 .rho.V.sup.2). The two measurements can be used to compute mass flow rate.